gogen - Code generator for the Go language

gogen is a general-purpose Go code generation toolkit. Like the Go compiler, It can perform type checking of expressions. For example, if you generate an expression like "Hello" + 1, it will report the corresponding error.

Quick start

Create a file named hellogen.go, like below:

package main

import (
	"go/token"
	"go/types"
	"os"

	"github.com/goplus/gogen"
)

func main() {
	pkg := gogen.NewPackage("", "main", nil)
	fmt := pkg.Import("fmt")
	v := pkg.NewParam(token.NoPos, "v", types.Typ[types.String]) // v string

	pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg).
		DefineVarStart(token.NoPos, "a", "b").Val("Hi").Val(3).EndInit(2). // a, b := "Hi", 3
		NewVarStart(nil, "c").VarVal("b").EndInit(1).                      // var c = b
		NewVar(gogen.TyEmptyInterface, "x", "y").                          // var x, y interface{}
		Val(fmt.Ref("Println")).
		/**/ VarVal("a").VarVal("b").VarVal("c"). // fmt.Println(a, b, c)
		/**/ Call(3).EndStmt().
		NewClosure(gogen.NewTuple(v), nil, false).BodyStart(pkg).
		/**/ Val(fmt.Ref("Println")).Val(v).Call(1).EndStmt(). // fmt.Println(v)
		/**/ End().
		Val("Hello").Call(1).EndStmt(). // func(v string) { ... } ("Hello")
		End()

	pkg.WriteTo(os.Stdout)
}

Try it like:

go mod init hello
go mod tidy
go run hellogen.go

This will dump Go source code to stdout. The following is the output content:

package main

import "fmt"

func main() {
	a, b := "Hi", 3
	var c = b
	var x, y interface{}
	fmt.Println(a, b, c)
	func(v string) {
		fmt.Println(v)
	}("Hello")
}